1. Field of the Invention
2. Description of Related Art
The invention relates to a method for drying in a household appliance, e.g. a laundry drier, dishwashing machine or shoe drier.
For drying, for example, it is known that a dishwashing machine has a washing method whose program run consists of at least one partial program step “pre-rinse”, a “clean” section, at least one partial program step “intermediate rinse”, a partial program step “clear rinse” and a partial program step “dry”. The rinsing liquid is heated before or after a partial program step to enhance the cleaning effect. The rinsing liquid is usually heated using electrical heaters in the dishwasher and/or by supplying hot water from the domestic installation. Various drying systems are known for drying washed dishes in a dishwashing machine.
For example, the washed dishes in a dishwashing machine can be dried by own-heat drying if the rinsing liquid is heated in a partial program step “clear rinse” and thus the washed dishes which have undergone a hot clear rinse are dried by themselves by the material-dependent heat content of the washed dishes which has thus built up. In order to achieve this own-heat drying, the rinsing liquid is heated to a certain temperature by a separate heater in the “clear rinse” partial program step and applied to the washed dishes by means of spraying devices provided in the dishwashing machine. As a result of the relatively high temperature of the rinsing liquid in the “clear rinse” partial program step of usually 55° C. to 75° C., it is achieved that a sufficiently large quantity of heat is transferred to the washed dishes so that residual water adhering to said washed dishes vaporises as a result of the heat stored in the washed dishes. The vapor condenses on colder surfaces or is removed from the dishwasher by means of a fan.
In a further known drying device, for example, in a dishwashing machine, a separate heat source, e.g. a hot air fan, is used in the washing container to heat the moist air mixture during the drying process so that the air in the washing container can absorb a larger quantity of moisture. A disadvantage in the heating systems described above according to the prior art described in dishwashing machines, for example, is that the heating of the rinsing liquid is associated with a relatively high energy requirement and the thermal energy required for each heating phase must be produced anew by means of electrical heating elements. The known heating systems also have the disadvantage that the heating of the rinsing liquid in the “clear rinse” partial program step and the processes in the “drying” partial program step are themselves associated with a high energy requirement and the thermal energy required is lost after the drying process because this escapes to the environment.
Dishwashers are known in which the moist air is vented outwards. This is disadvantageous since the surrounding kitchen furniture is damaged and the method requires a possibly unhygienic supply of air into the dishwasher from outside.
Furthermore, dishwashers are known in which the moist air is passed over condensing surfaces on which the moisture condenses before being guided out. This condensation is either passed into the washing container or into special collecting containers.
Known from DE 30 21 746 A1, for example, is a method for operating a dishwashing machine, wherein a heat exchanger connected to the washing container in a heat-conducting manner is supplied with cold fresh water during a partial program step “dry”. As a result, a condensation surface is produced on the inside of the washing container on which the moisture condenses and the condensation formed stays in the washing container. Since the temperature difference between the moist air and the fresh water which has been poured in is relatively small and the quantity of fresh water is continuously heated, the disadvantage arises that the condensation of the moist air takes a long time and the condensation performance is continuously reduced and the duration of the partial program step “dry” is long with a moderate drying result. With the duration of the drying process, the bacteria always present on the washed dishes are stimulated to rapid growth by the moist warm environment.